Transient electronics (or biodegradable electronics) is an emerging technology whose key characteristic is an ability to dissolve, resorb, or physically disappear in physiological environments in a ...controlled manner. Potential applications include eco-friendly sensors, temporary biomedical implants, and data-secure hardware. Biodegradable electronics built with water-soluble, biocompatible active and passive materials can provide multifunctional operations for diagnostic and therapeutic purposes, such as monitoring intracranial pressure, identifying neural networks, assisting wound healing process, etc. This review summarizes the up-to-date materials strategies, manufacturing schemes, and device layouts for biodegradable electronics, and the outlook is discussed at the end. It is expected that the translation of these materials and technologies into clinical settings could potentially provide vital tools that are beneficial for human healthcare.
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•A variety of biodegradable materials for transient electronics are reviewed.•Novel fabrication schemes are discussed.•Representative biodegradable devices are highlighted.•Perspective to further advance biodegradable electronics is provided.
Biodegradable and soft biomedical electronics that eliminate secondary surgery and ensure intimate contact with soft biological tissues of the human body are of growing interest, due to their ...emerging applications in high-quality healthcare monitoring and effective disease treatments. Recent systematic studies have significantly expanded the biodegradable electronic materials database, and various novel transient systems have been proposed. Biodegradable materials with soft properties and integration schemes of flexible or/and stretchable platforms will further advance electronic systems that match the properties of biological systems, providing an important step along the path towards clinical trials. This review focuses on recent progress and achievements in biodegradable and soft electronics for biomedical applications. The available biodegradable materials in their soft formats, the associated novel fabrication schemes, the device layouts, and the functionality of a variety of fully bioresorbable and soft devices, are reviewed. Finally, the key challenges and possible future directions of biodegradable and soft electronics are provided.
Abstract
Real-time sensing of nitric oxide (NO) in physiological environments is critically important in monitoring neurotransmission, inflammatory responses, cardiovascular systems, etc. ...Conventional approaches for NO detection relying on indirect colorimetric measurement or built with rigid and permanent materials cannot provide continuous monitoring and/or require additional surgical retrieval of the implants, which comes with increased risks and hospital cost. Herein, we report a flexible, biologically degradable and wirelessly operated electrochemical sensor for real-time NO detection with a low detection limit (3.97 nmol), a wide sensing range (0.01–100 μM), and desirable anti-interference characteristics. The device successfully captures NO evolution in cultured cells and organs, with results comparable to those obtained from the standard Griess assay. Incorporated with a wireless circuit, the sensor platform achieves continuous sensing of NO levels in living mammals for several days. The work may provide essential diagnostic and therapeutic information for health assessment, treatment optimization and postsurgical monitoring.
Abstract
Ce
3+
-doped yttrium aluminum garnet (YAG:Ce) nanocrystals were successfully synthesized via a facile sol-gel method. Multiple characterization techniques were employed to study the ...structure, morphology, composition and photoluminescence properties of YAG:Ce nanophosphors. The YAG:Ce
0.0055
sintered at 1030 °C exhibited a typical 5
d
1
-4
f
1
emission band with the maximum peak located at 525 nm, and owned a short fluorescence lifetime
τ
1
(~28 ns) and a long fluorescence lifetime
τ
2
(~94 ns). Calcination temperature and Ce
3+
doping concentration have significant effects on the photoluminescence properties of the YAG:Ce nanophosphors. The emission intensity was enhanced as the calcination temperature increased from 830 to 1030 °C, but decreased dramatically with the increase of Ce
3+
doping concentration from 0.55 to 5.50 at.% due to the concentration quenching. By optimizing the synthesized condition, the strongest photoluminescence emission intensity was achieved at 1030 °C with Ce
3+
concentration of 0.55 at.%.
Recently,
sp., a kind of filamentous microalgae, has been studied for biofuel production due to its accumulation of triacylglycerols. However, the polysaccharides of
sp. and their biological ...activities have rarely been reported. In this paper, we extracted sulfated polysaccharides from
sp. (TSP), characterized their chemical composition and structure, and determined their immunostimulation and anticancer activities on RAW264.7 macrophage cells and HepG2 cells. The results showed that TSP is a sulfated polysaccharide with a M
of 197 kDa. TSP is a heteropolysaccharide that is composed mainly of galactose. It showed significant immune-modulatory activity by stimulating macrophage cells, such as upregulating interleukin 6 (IL-6), interleukin 10 (IL-10), and tumor necrosis factor α (TNF-α). In addition, TSP also showed significant dose-dependent anticancer activity (with an inhibition rate of up to 66.8% at 250 µg/mL) on HepG2 cells as determined by the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The cycle analysis indicated that the anticancer activity of TSP is mainly the result of induced cell apoptosis rather than affecting the cell cycle and mitosis of HepG2 cells. These findings suggest that TSP might have potential as an anticancer resource, but further research is needed, especially in vivo experiments, to explore the anticancer mechanism of TSP.
This paper is part of a special issue on Music Technology. We study the type recognition of traditional Chinese musical instrument audio in the common way. Using MEL spectrum characteristics as ...input, we train an 8‐layer convolutional neural network, and finally achieve 99.3% accuracy. After that, this paper mainly studies the performance skill recognition of Chinese traditional musical instruments. Firstly, for a single instrument, the features were extracted by using the pre‐trained ResNet model, and then the SVM algorithm was used to classify all the instruments with an accuracy of 99%. Then, in order to improve the generalization of the model, the paper proposes the performance skill recognition of the same kind of instruments. In this way, the regularity of the same playing technique of different instruments can be utilized. Finally, the recognition accuracy of the four kinds of instruments is as follows: 95.7% for blowing instruments, 82.2% for plucked‐string instruments, 88.3% for strings instruments, and 97.5% for percussion instruments. We open source the audio database of traditional Chinese musical instruments and the Python source code of the whole experiment for further research.
The article presents the design and development of a virtual fretless Chinese stringed instrument App with the Duxianqin as an example, whose performance is expected to be no different from a real ...instrument. The digital simulation of fretless musical instruments is mainly divided into two parts: the simulation of the continuous pitch processing of the strings, and the simulation of the sound produced by plucking strings. The article returns to the theory of mechanics and wave theory and obtains the quantitative relationship between string frequency and its deformation and elongation. The Duxianqin selected in this article is a fretless instrument, which cannot be completely simulated by relying solely on sound source data. Playing and vocalization require real‐time synthesis through pitch processing, which has certain reference significance for the realization of other fretless instruments.
Face recognition technology despite its extensive application across various domains. However, occlusion factors like masks and glasses are significantly impeded by current face recognition models, ...resulting in limitations to their practical usage. We present Occlusion-Aware Module Network called Occlusion-Aware Module-based Network (OAM-Net), designed to enhance the accuracy of occluded face recognition. OAM-Net comprises two sub-networks: an occlusion-aware sub-network and a key-region-aware sub-network. The occlusion-aware sub-network incorporates an attention module to adaptively modify the weights of convolutional kernels for optimizing the processing of occluded face images. Meanwhile, the key-region-aware sub-network integrates a Spatial Attention Residual Block (SARB) for precise identification and localization of key facial regions. The network's generalization performance and accuracy are further enhanced by implementing a meta-learning-based strategy to boost the network's generalization performance and accuracy. Experimental results affirm OAM-Net's superior performance of OAM-Net over other state-of-the-art methods in occluded face recognition, underlining its significant potential for practical application.
As a popular marine saccharide, chitooligosaccharides (COS) has been proven to have good antioxidant activity. Its antioxidant effect is closely related to its degree of polymerization, degree of ...acetylation and sequence. However, the specific structure–activity relationship remains unclear. In this study, three chitosan dimers with different sequences were obtained by the separation and enzymatic method, and the antioxidant activity of all four chitosan dimers were studied. The effect of COS sequence on its antioxidant activity was revealed for the first time. The amino group at the reducing end plays a vital role in scavenging superoxide radicals and in the reducing power of the chitosan dimer. At the same time, we found that the fully deacetylated chitosan dimer DD showed the strongest DPPH scavenging activity. When the amino groups of the chitosan dimer were acetylated, it showed better activity in scavenging hydroxyl radicals. Research on COS sequences opens up a new path for the study of COS, and is more conducive to the investigation of its mechanism.
The monobactams, exemplified by the natural product sulfazecin, are the only class of β-lactam antibiotics not inactivated by metallo-β-lactamases, which confer bacteria with extended-spectrum ...β-lactam resistance. We screened a transposon mutagenesis library from Pseudomonas acidophila ATCC 31363 and isolated a sulfazecin-deficient mutant that revealed a gene cluster encoding two non-ribosomal peptide synthetases (NRPSs), a methyltransferase, a sulfotransferase, and a dioxygenase. Three modules and an aberrant C-terminal thioesterase (TE) domain are distributed across the two NRPSs. Biochemical examination of the adenylation (A) domains provided evidence that L-2,3-diaminopropionate, not L-serine as previously thought, is the direct source of the β-lactam ring of sulfazecin. ATP/PPi exchange assay also revealed an unusual substrate selectivity shift of one A domain when expressed with or without the immediately upstream condensation domain. Gene inactivation analysis defined a cluster of 13 open reading frames sufficient for sulfazecin production, precursor synthesis, self-resistance, and regulation. The identification of a key intermediate supported a proposed NRPS-mediated mechanism of sulfazecin biosynthesis and β-lactam ring formation distinct from the nocardicins, another NRPS-derived subclass of monocyclic β-lactam. These findings will serve as the basis for further biosynthetic research and potential engineering of these important antibiotics.
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•The first monobactam biosynthetic gene cluster is isolated and characterized•Two non-ribosomal peptide synthetases play essential biosynthetic roles•A new mechanism of β-lactam formation is catalyzed in an aberrant thioesterase domain
Li et al. isolate and characterize the first monobactam biosynthetic gene cluster. A non-ribosomal peptide synthetase is proposed to assemble a tripeptide precursor and form the key β-lactam ring of this antibiotic class by a mechanism distinct from the three other previously known strategies.
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